1. Field
This invention relates generally to the manufacture of semiconductor devices, and more specifically to metrology tools used in the manufacture of semiconductor devices.
2. Background
Semiconductor metrology tools used in semiconductor manufacturing to measure and characterize wave front data generally rely on a high degree of component alignment within the tool. In general, the alignment of components within a metrology tool affect the performance of the tool. For example, if optical components within the tool are not aligned to each other correctly, optical distortions can adversely affect the tool's performance. To improve the performance of the tool, methods of characterizing component alignment have been developed, and component alignment data can be used for calibration and correction of data gathered with the tool. See, for example, U.S. Pat. No. 5,828,455 entitled “Apparatus, Method of Measurement and Method of Data Analysis for Correction of Optical System” to A. Smith et al., issued Oct. 27, 1998; and U.S. Pat. No. 6,356,345 entitled “In-Situ Source Metrology Instrument and Method of Use” to B. McArthur et al., issued Mar. 12, 2002, both of which are assigned to the assignee of the present application and are herein incorporated in their entirety.
While techniques have been developed to characterize component alignment, the techniques often require the use of optical components and equipment that are not part of the tool used to determine component alignment. It would be advantageous not to have to use additional optical components or equipment to characterize the tool.
There is, therefore, a need in the art for improving the characterization of component alignment of metrology tools.